1. Field of the Invention
The present invention relates generally to a solid-state switch driving circuit for a vehicle and, more particularly, to a solid-state switch driving circuit for a vehicle, which selectively allows and interrupts the application of voltage from a vehicle battery to a load (i.e., an electric device).
2. Description of the Related Art
A conventional power switch for a vehicle employs a power relay. The anode of a battery (B+, 12 V) is connected to the top of the coil of the power relay, and a ground GND is connected to the bottom of the coil. Accordingly, B+ voltage should be applied to the top of the coil in order to drive the power relay.
When the B+ battery power is applied to the coil, current flows through the coil, the relay turns on the switch, and therefore the battery power is applied to a load.
In this case, problems arise in that the contact of the relay may be damaged by an excessive inrush current when the relay is turned on and peripheral circuits may be damaged because surge voltage is applied to the peripheral circuits when the relay is turned off.
The peripheral circuits may not operate stably because of the introduction of high surge voltage generated at this time. Moreover, another problem arises in that a short circuit may occur between the coil of the power relay and the ground because voltage is always applied to the coil.